This disclosure relates generally to electrical switches. More particularly, this disclosure relates to electrical switches which are responsive to fluid flow in a fluid system.
It is quite conventional to employ electrical switches which are responsive to the flow of a fluid through a conduit of a fluid system. Such switches are employed to regulate the fluid flow to inject various substances into the fluid system and to activate various controls and auxiliary devices. It is very common to employ reed switches and Hall effect sensors for electrical switching functions in fluid flow systems.
Reed switches are relatively sensitive and are prone to failure due to repetitive mechanical shock. In addition, the reed switch cannot typically operate at a substantial current, and is conventionally operated at milliamp level current. Thus, the reed switch operates a small relay which tends to be connected to larger relays. Electrical spikes damage reed-type switches.
The Hall effect-type switch also has some of the same deficiencies. In addition, heat changes the closing/opening range—the so-called pull-in (to close the switch and so-called drop-out when the magnet moves away from the switch. Both the reed switch and Hall effect switch rely on the integrity of the magnetic flux. The contacts in the reed switch due to repetitive opening and closing and the generated heat causes the magnet to diminish and the integrity of the magnetic flux required to replicate the operation to diminish. The magnetic components of the switches commonly may attract various materials which also otherwise detract from reliable operation over time. Ferrous (magnetic) materials build up on the attracting magnet also causes the swinging or motion to jam up in close proximity to the reed switch.
The present disclosure is directed to a flow switch which is not subject to any deficiencies or problems associated with magnetic components or magnetic flux required to effectively operate a conventional switch over an extended lifetime of usage.